Pain represents a large and dynamic market. Non-steroidal anti-inflammatory drugs (NSAIDs) are among the most commonly prescribed drugs worldwide and are responsible for approximately one-quarter of all adverse drug reaction reports. NSAIDs are widely prescribed for patients with rheumatic disease, a population at increased risk for serious gastrointestinal (GI) complications. Topical administration of NSAIDs offers the advantage of local, enhanced drug delivery to affected tissues with a reduced incidence of systemic adverse effects, such as peptic ulcer disease and GI hemorrhage. Thus, treating pain topically is preferred as it delivers the active drug molecules to where the pain and inflammation are locally and avoids the so-called first-pass metabolism thus minimizing systemic exposure and adverse effects. There is growing physician and patient interest in and demand for prescription therapies that can deliver safe, effective and convenient site-specific pain management.
There are many technical challenges in topically delivering drugs through skin. NSAIDs administered topically penetrate slowly and in small quantities into the systemic circulation; bioavailability and maximal plasma NSAID concentration after topical application are generally less than 5 and 15%, respectively, compared with equivalent oral administration. Product formulation has a dramatic impact on topical delivery success such as on drug penetration rate, skin irritation, and product stability. Therefore, it is not surprising that prescription-strength topical NSAIDs have only been available in the US since early 2008.
The art is replete with the ways of dealing with pain and inflammation, both in humans and animals. The medical literature and patents around the world describe many ways in which these conditions can be treated, with greater or lesser success in any given situation. Oral-administered dosage forms are one suitable, if not the primary, form of administration of analgesic and anti-inflammatory drugs. Oral administration is necessarily systemic, thus causing, in many instances, unwanted, adverse side effects. Another form of administration is topical where the drug is administered locally through the skin. One form of topical administration is by use of patches, which can take many different forms. This invention pertains to novel matrix-type patches containing piroxicam for the transdermal treatment of pain and inflammation.
It would be desirable to provide novel matrix patches for topical application of piroxicam and methods for the treatment of acute and chronic pain and inflammation therewith. The matrix patches of this invention have excellent drug penetration though the skin, meaning that more piroxicam is delivered thereby enabling small patches to be used to achieve the administration of a given, therapeutically effective amount of the piroxicam over a given period of time. This should result in better clinical efficacy and reduced side effects than with administration of comparable amounts of the piroxicam orally or systemically. In addition, the matrix patches of this invention have excellent physical and chemical stabilities, necessary for useful and commercially viable products. The matrix patches of this invention are extremely compatible with mammalian skin with little or no skin irritation.